[ncl-talk] Code Compiling Extremely Slowly

[Zach Rieck]

Thanks Rick!

I think the thing that slows it down most is the do loop from 70-77 for
some reason. Not sure if they arguments I'm using could be more specific to
avoid pulling in so much data. Hard to tell, and I agree I wish that NCL
was more efficient with that! Us programmers who are used to doing loops
really need them.

I got the divergence issue figure out, just had a -1 inside a parenthesis
when it should have been outside.

-Zach Rieck
zrr817 at gmail.com
(513)-502-5652


On Tue, Aug 6, 2019 at 8:36 PM Rick Brownrigg <brownrig at ucar.edu> wrote:

> Hi Zach,
>
> Just a comment and a conjecture:  NCL's string processing is notoriously
> inefficient when the number of strings involved gets large (something I'd
> dearly loved to have fix, but...).  With that in mind, I wonder if the
> string processing around lines 22-41 might be the problem, in which you
> convert the variable Time coming out of the WRF files to strings, and then
> use the str_get_cols() function to pick out pieces of year/month/day/etc.
>
> I don't really know much about it, but as far as I can tell, the Time
> variable from a WRF file is character[*][*]?   Converting sequences of
> characters to integers does not seem to be directly supported, but you
> might try something like:
>
> ncl 1> time = (/50C,48C,49C,57C, 48C, 56C, 48C, 54C/)  ; funky notation
> for character literals; this should be today's date: 20190806
> ncl 2> print("year = " + tointeger(str_get_cols(time,0,3)))
> ncl 3> print("mon = " + tointeger(str_get_cols(time,4,5)))
> ncl 4> print("day = " + tointeger(str_get_cols(time,6,7)))
>
> This works, but I don't know if its an improvement; it issues warnings to
> the effective of:
>
> warning:Argument 0 of the current function or procedure was coerced to the
> appropriate type and thus will not change if the function or procedure
> modifies its value
>
> I don't know if, under the hood, "coercion" is more efficient than
> straight up conversion.
>
> I am not qualified to address the science question about the divergence of
> the curves.
>
> Good luck!
> Rick
>
>
> On Tue, Aug 6, 2019 at 5:50 PM Zach Rieck via ncl-talk <ncl-talk at ucar.edu>
> wrote:
>
>> To Whom it May Concern-
>>
>> I have been having an issue with a plot I have generated with this code
>> file, and I need to be able to quickly troubleshoot the data it is pulling
>> in. My code seems to be doing exactly what I want, but I'm curious if
>> there's anyway to make it run faster/more efficiently? I know this may
>> difficult since I'm having to skip over a bunch of time periods and
>> organize a lot of data into different sized groups, so if the answer is I
>> can't, that's fine.
>>
>> I've attached the figure in question as well just in case you see
>> anything that might be causing the spread near the top of the figure. I've
>> gone through my code very carefully, and I'm pretty sure it's an issue with
>> the dataset, but if you notice anything else I can try fixing please let me
>> know.
>>
>> Thanks in advance for the help!
>>
>> Respectfully,
>>
>> -Zach Rieck
>> zrr817 at gmail.com
>> (513)-502-5652
>> _______________________________________________
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